expects to receive a user name and password from the dialing router with both PAP and CHAP.
With PAP, the user name and password are sent by the dialing router. With CHAP, the dialed-
to router sends a message (called a challenge) that asks the dialing router to send its user name
and password. The challenge includes a random number, which is part of the input into the MD5
hash algorithm. The dialing router replies with the MD5 hash value, which is a function of its
ID (host name), its password, and the random number supplied in the challenge. The dialed-to
router repeats the same hash algorithm; if the received value matches the computed value, the